1. Field of the Invention
The invention relates to a hoist for roll material surface treatment and particularly to an apparatus which has power transmission means and rotary shaft to enable a roll material rotating in the processing liquid for achieving uniform surface treatment.
2. Description of the Prior Art
A roll or coil material is usually formed by winding and laminating a thin strip of material such as steel wire or sheet in annular crossection.
As steel wire or sheet is formed by drawing, extension or extrusion during the production process, it prones to oxidize. Oxidization also takes place when a roll of steel wire or sheet being stored in the stockroom. It therefore needs surface treatment to prevent exidization.
Conventional surface treatment for roll material includes an electric hoist to suspend a roll material in the processing liquid and to generate up and down vibration on the roll for allowing processing liquid to sip between laminates and cover the surface of the material. As the roll of material being laminated and stacked tightly, it usually results in too small gap between two laminates. Processing liquid can not uniformly covers the entire surface thus resulting in not effective surface treatment.